The present invention relates to decorative lighting and in particular to a liquid motion lamp.
Liquid motion lamps, commonly called “lava lamps” have been know since the 1960s. Such lamp is described in U.S. Pat. No. 3,387,396 for “Display Devices.” The '396 patent describes a lamp having globules of a first liquid suspended in a second liquid, wherein the first liquid has a thermal expansion coefficient providing sufficient expansion, and therefore reduction in density, such that the first liquid is heavier than the second liquid at a lower temperature, and lighter than the second liquid at a higher temperature. The temperatures may be, for example 45 degrees Centigrade and 50 degrees Centigrade. The first and second liquids are contained in a clear container having a heat source at the bottom, and as a result, the first liquid is heated, rises within the second liquid, cools, and drops back to the bottom of the container. At least one of the liquids is preferably colored, and provides an entertaining motion for an observer. Lamps such as described by the '396 patent are typically small and are sold as a sealed unit.
Recently, liquid motion lamps have gained popularity, and there is a desire to use such lamps in various commercial settings, for example hotel lobbies, clubs, lounges, etc. Unfortunately, simply scaling up known liquid motion lamps results in a product very expensive to ship, and which require as much as an eight hour or more warm-up period before use.